Todos for aggregator in new planner:

[xudong963]

The following is todos for aggregator in new planner:

• count(*), count(col), count(1)
• select sum(a) from t;
• select count(a) from t;
• select count() from t group by a;
• select count() from t;
• select count(*) from t;
• select count(1) from t;
• select count(1) from t group by a;
• There is a bug when the table contains multiple columns
• support having feat(planner): support having and scalar expression in group by for new planner #5131
• support scalar expression, such as a + 1, b + 1 in group by
• https://dev.mysql.com/doc/refman/8.0/en/group-by-handling.html, the aggregation function supports the inclusion of columns that are not in the group by: low pri

Originally posted by @xudong963 in #5115 (comment)

[xudong963]

Feel free to edit the issue if you have something to add :)